In fine, the radical difference between inorganic units, like atoms, molecules, and multimolecules, and living units, like protozoans and metazoans, is so obvious that it is universally admitted. Not all, however, are in accord when it comes to assigning the fundamental reason for the difference in question. Benjamin Moore postulates a unique physical energy, peculiar to living organisms and responsible for all distinctively vital manifestations. This unique form of energy, unlike all other forms, he calls “biotic energy,” denying at the same time that it is a vital force. (Cf. _op. cit._, pp. 224-226.) Moore seems to be desirous of dressing up vitalism in the verbal vesture of mechanism. He wants the game, without the name. But, if his “biotic energy” is unlike all other forms of energy, it ought not to parade under the same name, but should frankly call itself a “vital force.” Somewhat similar in nature is Osborn’s suggestion that the peculiar properties of living protoplasm may be due to the presence of a unique chemical element called Bion. (Cf. “The Origin and Evolution of Life,” 1917, p. 6.) Now, a chemical element unlike other chemical elements is not a chemical element at all. Osborn’s Bion, like Moore’s biotic energy, ought, by all means, to make up its mind definitely on Hamlet’s question of “to be, or not to be.” The policy of “It is, and it is not,” is not likely to win the approval of either mechanists or vitalists. § 6. Hylomorphism versus Mechanism and Neo-vitalism Mechanism and Neo-vitalism represent two extreme solutions of this problem of accounting for the difference between living and lifeless matter. Strictly speaking, it is an abuse of language to refer to mechanism as a solution at all. Its first pretense at solving the problem is to deny that there is any problem. But facts are facts and cannot be disposed of in this summary fashion. Forced, therefore, to face the actual fact of the uniqueness of living matter, mechanists concede the inadequacy of their physicochemical analogies, but obstinately refuse to admit the legitimacy of any other kind of explanation. Confronted with realities, which simply must have _some_ explanation, they prefer to leave them unexplained by their own theory than have them explained by any other. They recognize the difference between a living animal and a dead animal (small credit to them for their perspicacity!), but deny that there is anything present in the former which is not present in the latter.